Always start by hanging the ceilings first. If you can, rent a drywall lift to raise the drywall and hold it into position while you screw the drywall off.
Again, try to minimize butt joints in the ceiling by using longer sheets of drywall whenever possible. If you have butt joints, stagger them so the butt joints are never in the same position.

Notice in the above picture the butt joints are offset?
Cut your drywall to length using a T-Square and a utility knife. Use a drywall rasp to smooth the cut edge. Also take note of the studs in the ceiling and mark on your drywall first - trust me, it's much easier to mark studs on the ground than it is on a ladder over your head with a 100 pound sheet of drywall hanging over you.
Screws usually are placed every 7-8" on the ceiling. Make sure your drywall screw bit is set right, so your screw head sits just below the surface of the drywall but does not break the paper.
Mark the location of all boxes on the ceiling and cut out with either a keyhole saw, or use a rotozip.

I'm a big fan of the rotozip, because you just have to mark the center of each box, and then with your rotozip bit set so it only cuts the thickness of your drywall with the remaining protruding part used only as a guide, you can go from the center to the outside of the box, then cut out around the outside of the box. This tool makes cutting boxes out a 30 second job.
Since the boxes protrude out 5/8" on ceilings (1/2" on walls), if you are cutting out in place, don't fully screw the sheet off first - you'll punch those boxes right through the drywall. Instead, just attach with a few screws to keep in place, then cut out your boxes, and then finish screwing the sheet off.
Wear a respirator, hearing and eye protection because it does get pretty messy though.
The walls are much easier than the ceiling, but you'll have more openings and boxes to deal with. Start by marking all stud and box locations on the floors. I also like to mark any no nail zones - like large ducting or venting pipes - on the floor just to be extra safe.
Start by hanging the upper portion of the wall. If your ceiling is uneven, you can snap a line 48" down from the ceiling, and then follow that line with the bottom edge of your drywall. I mark stud locations after hanging the sheet because I can just line the T-Square up with a stud, and mark, and then screw off.
Screws should be placed every 12" for walls, and again, screws need to be just below the drywall surface not breaking the paper.
Drywall right over doors and openings, and then go back and cut the opening out with a rotozip or keyhole saw. You want to minimize joints over doorways, as this is a high stress area, and the seam may crack from the doors being opened and closed.
Hang the lower portion next, using the roller lift tools to lift the drywall up so it meets the upper sheet. If you have to trim drywall widths because your walls are not quite 8 feet, cut so the cut edge is at the floor.
For electrical boxes, do as you did the ceiling - mark placement of the boxes and then cut out with either a keyhole saw or rotozip. If using the rotozip, again, just put a few loose screws in, rotozip out your boxes, and then finish screwing off the full sheet of drywall.
For the lower portion, keep the bottom row of screws on the bottom plate to minimize mudding later on. This all gets covered by your baseboard.
For corners, if you are bullnosing, cut the corners to the ends of the studs, not overlapping the drywall, so the outside edges of the drywall do not meet.

The bullnose trim will not fit otherwise.
You can do this - just keep at it and do a good job, and you'll be amazed at how much work gets done pretty easily!